ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1624 www.ijaegt.com
The Use of Carbon-Nanotubes for Removal of Bacterial Pathogens
from River Water
Hassaan, A.M.a, El-kady, M.A.
b, Nasser, A.
a, Etman, M.
c, Omar, M.
d
a Higher Technological Institute, Tenth of Ramadan City, Egypt.
b Faculty of Engineering, Al Azhar University, Cairo, Egypt.
c Pyramids higher institute, Egypt.
d
Faculty of Engineering, Misr University of Science and technology, Cairo, Egypt.
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
ABSTRACT
Providing clean and affordable water to meet human needs is a grand challenge of the 21st
century. Worldwide, water supply struggles to keep up with the fast growing demand, which is
exacerbated by population growth, global climate change, and water quality deterioration. The
need for technological innovation to enable integrated water management cannot be overstated.
Nanotechnology holds great potential in advancing water and wastewater treatment to improve
treatment efficiency as well as to augment water supply through safe use of unconventional
water sources. Carbon nanotubes (CNTs) are microscopic, hollow, cylindrical tubes made out of
graphene sheets. They contain several different, unique functions. Two functions in particular,
mechanical and antimicrobial, cause nanotubes to be lethal to microbacteria, as well as being
small, strong and flexible. This has allowed nanotubes to be produced as decontaminant filters.
The main objective of the present study is to develop a filter targeting the removal of microbial
pathogens from river water. An experimental setup was constructed in which the multiwall
carbon nanotubes (MWCNT) are used directly as a layer in the filter. The parameters
investigated in the present work includes; the pressure, the temperature, the quantity of MWCNT
utilized, and the thickness of MWCNT.
The present investigation reveals that the percentage reduction in total bacterial count, total
coliforms count, fecal coliforms count and fecal streptococci count increases with the increase of
the water temperature and larger thickness of CNTs. However, increase water pressure results in
lower percentage reduction in total bacterial count, total coliforms count, fecal coliforms count
and fecal streptococci count.
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
1. .Introduction
Access to safe drinking water is a basic
necessity for human life [1]. Water crisis is
one of the greatest challenges of the present
time. The lack of fresh and clean water is a
ubiquitous problem around the world [2]. To
address the undeniable need of pure water,
various water treatment technologies have
been proposed and applied at experimental
and field levels. These technologies are
commonly fall into primary (screening,
filtration, centrifugation, separation,
sedimentation, coagulation and
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1625 www.ijaegt.com
flocculation); secondary (aerobic and
anaerobic treatments); and tertiary
(distillation, crystallization, evaporation,
solvent extraction, oxidation, precipitation,
ion exchange, reverse osmosis (RO),
nanofiltration (NF), ultrafiltration (UF),
microfiltration (MF), adsorption, electrolysis
and electrodialysis) level water treatment
technologies [3]. In recent years,
nanotechnology has introduced different
types of nanomaterials to water industry that
can have promising outcomes. Since their
discovery in 1991 [4], carbon nanotubes
(CNTs) have attracted much attention in
various scientific communities, with a
myriad of applications in electronics,
composite materials, fuel cells, sensors,
optical devices, and biomedicine. Moreover,
CNTs, because of their high surface area,
electronic properties, and ease of
functionalization, have excellent
nanosorbent properties for filtering
contaminants from water [5, 6]. Previous
studies in this field have focused on the use
of bare CNTs or CNTs functionalized with
inorganic nanoparticles for adsorption of
inorganic contaminants and toxic metals
from water [7-9]. Other studies have
explored the use of CNTs for adsorption of
low molecular weight organic contaminants
[10] and toxins [11] from water.
In particular, CNTs have been studied as
filters for the removal of viruses or bacteria.
Single-walled carbon nanotube (SWCNT)
filters have shown high bacterial retention
[12], and multi-walled carbon nanotube
(MWCNT) filters have high viral removal
efficiency at low pressure [13], both through
the effects of size exclusion. Moreover, a
SWCNT-MWCNT hybrid filter achieved
efficient bacterial inactivation and viral
retention at low pressure [14]. The
application of an external electric field
markedly enhanced the viral removal by the
CNT filter, because of the increased viral
particle transport [15]. Also, CNTs have
been studied as filters for the removal of
heavy metals and natural organic matter
(NOM) [16-19]. Furthermore, in order to
enhance the antibacterial ability of the CNT
filter, vertically aligned MWCNT arrays
were combined with silver nanoparticles
[20, 21], and CNT/cotton membrane was
combined with silver nanowires [22]. A
recent study demonstrated scalable
applications of this technology that use low-
cost and widely available CNTs for
inactivation of microbes [23-25]. For viral
removal by CNT-hybrid filters, filtration
performance was also tested under various
solution chemistries [26].These CNT-based
filters remove the micrometer-sized bacterial
cells through a sieving mechanism, whereas
depth (physicochemical) filtration governs
the adsorption of nanoscale viruses
throughout the thickness of the matrix [27].
The present study aims at the use of CNTs
as a sandwich layer in the filter as a method
of raw water purification. The raw water
samples are withdrawn from an urban
natural stream. The removal of natural
contaminants and suspended particles found
in such stream is studied. Also the removal
of any probable infectants as bacteria will be
presented. The study parameters include
temperature variation which was not
presented in such survey. Also the amount
of CNT filters is taken into consideration.
The effect of pressure variation of the water
inlet to the filter also will also be
investigated.
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1626 www.ijaegt.com
2. Experimental Technique
2.1. Materials Multi-walled CNTs type was used in
the process of water disinfection in the
present study. Multi-walled CNTs
(MWCNTs) with different functional groups
were purchased from Cheap Tubes Inc.
(Vermont, USA). To provide consistency
among the CNTs under investigation, this
study was restricted to this single
commercial manufacturer. Important
characteristics and unit costs (as reported by
the manufacturer) of CNTs used in the
experiments are shown in Table 1.
According to the manufacturer, the pristine
CNTs were prepared using chemical vapor
deposition and further purified or
functionalized using plasma methods.
The river water used in this study was
obtained from Ismailia Canal. The collected
water preserved at the room temperature in a
clean plastic tank for use in subsequent test
works.
Table 1 Characteristics of the used CNT:
Type of
CNT
Outer diameter
(nm)
Length
(μm)
Specific surface area
(m2/g)
Purity
(wt%)
Unit cost
($/g)
MWCNT 20 - 40 10 - 30 >110 >90 0.54
2.2. General Description of the
Experimental Test-Rig
The paraphernalia in figure (1) illustrates
the setup of the laboratory-scale water
treatment plant which is designed and
constructed to be used to evaluate the use of
CNTs as adsorption granular filter media. It
is constructed mainly of two stages; the first
stage consists of two tubes used for filtration
process to get rid of any material or
impurities found in raw river water which
helps to keep CNT pipes longer in use.
These tubes contain more than one element
of the traditional elements that are used in
water purification. The most common
material used in water purification is sand.
Sand of high quality has been used in this
research. Active carbon is also used in the
water purification process within the filter,
and to remove odors. The tubes are
filled with the same size and thickness of the
sand layer (of fine sand and coarse grains)
and the active carbon layer.
Another layer of materials that is used
during the first stage of water purification is
a layer of polypropylene (PP). This layer is
located at the end of each tube so as to
reserve both of sand and active carbon from
coming out with filtered water, and also to
improve the water purification process
before it enters the second phase of
disinfection.
The second stage of the laboratory-scale
water treatment plant is the stage of
disinfection. This stage contains a tube and
there are two layers of PP material inside
this tube between them the layer of CNT is
put as a sandwich. This layer is responsible
for retaining the bacteria from the water to
make it safe for drinking.
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1627 www.ijaegt.com
A water heating system is employed in the
present test rig to examine the effect of inlet
water temperature on the purification
process. The parameters considered in the
present investigation include inlet water
temperature and pressure, as well as CNT
amount and thickness.
Samples were collected in one liter sterilized
wide mouth glass bottles. These bottles were
presterilized at 180oC for 30 minutes.
Bottles were transported in sampling cooled
box to the national research center to be
examined within four hours form collection.
Figure (1) The Setup of the Laboratory-Scale Water Treatment Plant.
3. Results and Discussion
The effect of water pressure, water
temperature, thickness of carbon nanotubes
(CNT), and the amount of the CNT, on the
total bacterial count for samples at the
human blood temperature (37oC), and the
average water temperature (22oC), are
investigated.
3.1 Effect of the Water Pressure
The variation of percentage reduction of
total bacterial count per 1 ml versus water
pressure at two different temperatures 37 oC
and 22 o
C for the same inner diameter of 54
mm and different masses of carbon
nanotubes is shown in the figures (2a – 2c).
It is observed that, a decrease of the
percentage reduction in total bacterial count
for the analysis at 37 oC and 22
oC is
associated with the increase of water
pressure. Raising water pressure may push
water including bacteria through the CNT
holes, however, the disinfection process is
done by the retainment of the bacteria on the
outer surface of the CNT. Therefore, the
water pressure may force the bacteria
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1628 www.ijaegt.com
approximating to the size of CNT holes to
get out through the CNT hexagons holes.
It is also shown in the figures that, the
percentage reduction in the total count of
bacteria at the average water temperature
(22oC) is higher than that at the human
blood temperature (37oC). This can be
explained as follows; the bacteria at 22 oC
are weaker than the bacteria found at a
temperature of 37 o
C, so if exposed to any
external influence like a change in pressure
or temperature or made reservation to it, the
bacterial membrane may explode.
Meanwhile, at a temperature of 37 o
C, the
bacterial membrane may tend to vesiculation
to resist any external effects.
Figure (2a) Variation of Percentage Reduction of
Total Bacterial Count with Water Pressure for
Inner Tube Diameter = 54mm and CNT mass = 5,
10gm.
Figure (2b) Variation of Percentage Reduction of
Total Bacterial Count with Water Pressure for
Inner Tube Diameter = 54mm and CNT mass =
15, 20gm.
Figure (2c) Variation of Percentage Reduction of
Total Bacterial Count with Water Pressure for
Inner Tube Diameter = 54mm and CNT mass =
30, 40gm.
The variation of percentage reduction of
total coliforms count per 100 ml versus
water pressure for the same inner diameter
of 54 mm and different masses of carbon
nanotubes is shown in the figures (3a – 3c).
It is also observed that increasing water
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1629 www.ijaegt.com
pressure results in a decrease in the
percentage reduction in total coliforms
count.
Figure (3a) Variation of Percentage Reduction of
Total Coliforms Count with Water Pressure for
Inner Tube Diameter = 54mm and CNT mass = 5,
10 gm.
Figure (3b) Variation of Percentage Reduction of
Total Coliforms Count with Water Pressure for
Inner Tube Diameter = 54mm and CNT mass =
15, 20 gm.
Figure (3c) Variation of Percentage Reduction of
Total Coliforms Count with Water Pressure for
Inner Tube Diameter = 54mm and CNT mass =
30, 40 gm.
The variation of percentage reduction of
fecal sterptococci count per 100 ml versus
water pressure for the same inner diameter
of 54 mm and different masses of carbon
nanotubes is shown in the figures (4a – 4b).
It is noticed that, the percentage reduction in
fecal sterptococci count decreases as the
water pressure increases. The percentage
reduction is higher if compared with the
reduction of total coliforms count, this could
be attributed to the spherical shape of these
bacteria, and the nature of the outer surface
shape of the tubes, which results in retaining
larger amount of this bacteria.
3.2 Effect of the CNT Thickness
The variation of percentage reduction of
total bacterial count per 1 ml versus CNT
thickness at two different temperatures 37 oC and 22
oC for the different masses (20, 40
gm) of carbon nanotubes for the case in
which the water enters under gravity or
pressurized with the minimum pressure
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1630 www.ijaegt.com
needed to overcome the pressure drop
through the CNT is shown in the figures (5a
– 5b). As expected it is shown that,
increasing CNT thickness yields an increase
in the reduction of total bacterial count for
both temperatures.
Figure (4a) Variation of Percentage Reduction of
Fecal Streptococci Count with Water Pressure for
Inner Tube Diameter = 54mm and CNT mass = 5,
10, 15 gm.
Figure (4a) Variation of Percentage Reduction of
Fecal Streptococci Count with Water Pressure for
Inner Tube Diameter = 54mm and CNT mass =
20, 30, 40 gm.
This may be explained as follows; the
increase of CNT thickness causes the water
to take longer time to pass througth the layer
of the CNT which enhances the ability of
carbon nanotubes to retain a large amount of
bacteria from water.
Figure (5a) Variation of Percentage Reduction of
Total Bacterial Count with CNT Thickness for
CNT mass = 20 gm and Water Pressure 0, 3.3 bar.
Figure (5b) Variation of Percentage Reduction of
Total Bacterial Count with CNT Thickness for
CNT mass = 40 gm and Water Pressure 0, 4.5 bar.
The variation of percentage reduction of
total coliforms count per 100 ml versus CNT
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1631 www.ijaegt.com
thickness for the different masses (20, 40
gm) of carbon nanotubes for the case in
which the water exits under gravity or
pressurized with the minimum pressure
required to overcome the pressure drop
through the CNT is shown in figures (6a-
6b).
Figure (6a) Variation of Percentage Reduction of
Coliforms Count with CNT Thickness for CNT
mass = 20 gm and Water Pressure 0, 3.3 bar.
Figure (6b) Variation of Percentage Reduction of
Coliforms Count with CNT Thickness for CNT
mass = 20 gm and Water Pressure 0, 3.3 bar.
It is observed that, the increase of the
percentage reduction of total coliforms
count is associated with increasing the
thickness of the CNT. This may be a result
of increasing the retained coliforms due to
the longer time that the water takes to pass
from the CNT for larger thickness.
The variation of percentage reduction of
fecal streptococci count per 100 ml versus
CNT thickness for the different masses (20,
40 gm) of carbon nanotubes for the case in
which the water exits under gravity or
pressurized with the minimum pressure
needed to overcome the pressure drop
through the CNT is shown in the figures (7a
– 7b). The curves plotted in these figures
indicate that, increasing CNT thickness
reveal an increase in percentage reduction of
fecal streptococci count due to the increase
of the adsorption capacity with the increase
of CNT thickness.
Figure (7a) Variation of Percentage Reduction of
Fecal Streptococci Count with CNT Thickness for
CNT mass = 20 gm and Water Pressure 0, 3.3 bar.
3.3 Effect of the Water temperature
Figures (8a -8d) show the variation of
percentage reduction of total bacterial count
per 1 ml versus water temperature at two
different samples temperatures of 37 oC and
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1632 www.ijaegt.com
22 o
C for the two inner diameters (40, 54
mm) and two different masses of CNTs (20,
40 gm). Two cases are investigated; a case
in which the water exits under the gravity
and the other case in which the water exit
under the minimum pressure needed to
overcome the pressure drop in the CNT.
Figure (7b) Variation of Percentage Reduction of
Fecal Streptococci Count with CNT Thickness for
CNT mass = 40 gm and Water Pressure 0, 4.5 bar.
Figure (8a) Variation of Percentage Reduction of
Total Bacterial Count with Inlet Water
Temperature for Tube Inner Diameter = (40, 54
mm), CNT mass = 20 gm and P = 0 bar.
It is observed that, the percentage reduction
in total bacterial count for the both cases of
the sample analysis at 37 oC and 22
oC,
increase for higher water temperature. It
may be attributed to, the rise in temperature
of CNT which works to reduce the area of
the holes located on the surface of the tube
as a result of the expansion and contribute to
enhance the retention of bacteria.
Figure (8b) Variation of Percentage Reduction of
Total Bacterial Count with Inlet Water
Temperature for Tube Inner Diameter = (40, 54
mm), CNT mass = 20 gm and P = 3.3 bar.
Figure (8c) Variation of Percentage Reduction of
Total Bacterial Count with Inlet Water
Temperature for Tube Inner Diameter = (40, 54
mm), CNT mass = 40 gm and P = 0 bar.
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1633 www.ijaegt.com
Figure (8d) Variation of Percentage Reduction of
Total Bacterial Count with Inlet Water
Temperature for Tube Inner Diameter = (40, 54
mm), CNT mass = 40 gm and P = 4.7 bar.
Figures (9a – 9d) represent the variation of
percentage reduction of total coliforms
count per 100 ml versus water temperature
for the two inner diameters (40, 54 mm) and
two different masses of carbon nanotubes
(20, 40 gm). Two cases are considered, a
case in which the water exit under gravity
and the other case in which the water exit
under the minimum pressure needed to
overcome the pressure drop in the CNT.
Figure (9a) Variation of Percentage Reduction of
Coliforms Count with Inlet Water Temperature
for Tube Inner Diameter = (40, 54 mm), CNT
mass = 20 gm and P = 0 bar.
Figure (9b) Variation of Percentage Reduction of
Coliforms Count with Inlet Water Temperature
for Tube Inner Diameter = (40, 54 mm), CNT
mass = 20 gm and P = 3.3 bar.
Figure (9c) Percentage Reduction of Coliforms
Count Variation with Inlet Water Temperature
for Tube Inner Diameter = (40, 54 mm), CNT
mass = 40 gm and P = 0 bar.
The curves presented in these figures
indicated that, increasing water temperature
results in an increase in the percentage
reduction of coliforms count. This may be
explained as follows; CNT expands at
higher water temperature, this results in
more adsorbed capacity of CNTs especially
for low pressure. Such improvement in
adsorption capacity may yield water with
good quality to be used for human
consumption.
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1634 www.ijaegt.com
Figure (9d) Variation of Percentage Reduction of
Coliforms Count with Inlet Water Temperature
for Tube Inner Diameter = (40, 54 mm), CNT
mass = 40 gm and P = 4.7 bar.
The variation of percentage reduction of
fecal streptococci count per 100 ml versus
water temperature for the two inner
diameters (40, 54 mm) and two different
masses of carbon nanotubes (20, 40 gm)
under two cases, a case in which the water
exit gravity and under the minimum pressure
required to overcome the pressure drop in
the CNT is shown in figures (10a – 10d).
Figure (10a) Variation of Percentage Reduction of
Fecal Streptococci Count with Inlet Water
Temperature for Tube Inner Diameter = (40, 54
mm), CNT mass = 20 gm and P = 0 bar.
It is observed that, the percentage reduction
of fecal streptococci count slightly increases
with the increase of the water temperature.
This may be attributed to the same reasoning
mentioned before. However, the adsorption
capacity of CNTs for fecal streptococci is
much better than coliforms because it is
spherical shape.
Figure (10b) Variation of Percentage Reduction of
Fecal Streptococci Count with Inlet Water
Temperature for Tube Inner Diameter = (40, 54
mm), CNT mass = 20 gm and P = 3.3 bar.
Figure (10c) Variation of Percentage Reduction of
Fecal Streptococci Count with Inlet Water
Temperature for Tube Inner Diameter = (40, 54
mm), CNT mass = 40 gm and P = 0 bar.
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1635 www.ijaegt.com
Figure (10d) Percentage Reduction of Fecal
Streptococci Count Variation with Inlet Water
Temperature for Tube Inner Diameter = (40, 54
mm), CNT mass = 20 gm and P = 4.7 bar.
4. Conclusions
The following conclusions could be deduced
from the present work:
1- The percentage reduction in total
bacterial count, total coliforms count, fecal
coliforms count and fecal streptococci count
decrease with the increase of water pressure.
2- The percentage reduction in total
bacterial count, total coliforms count, fecal
coliforms count and fecal streptococci count
increase with the increase of the amount of
CNT.
3- However, decreasing the tube
diameter leads to increasing the thickness of
CNT layer; thereby enhance the efficiency
of the disinfection process.
4- The water temperature has
significant effect on the percentage
reduction in total bacterial count, total
coliforms count, fecal coliforms count, and
fecal streptococci count. The higher the
water temperature, the higher the efficiency
of the disinfection process.
5- The use of CNT in the disinfection
processes gives effective results and could
make raw water to be suitable for human
consumption.
5. References
[1] World Health Organization and
UNICEF, 2012. Progress on Drinking Water
and Sanitation: 2012 Update. Meeting the
MDG Drinking Water and Sanitation Target.
WHO/UNICEF, New York, NY. [2] Shannon, M. A., Bohn, P. W., Elimelech,
M., Georgiadis, J. G., Marinas, B. J., &Mayes,
A. M. (2008). Science and technology for water
purification in the coming decades. Nature,
452(7185), )301-310(.
[3] V.K. Gupta, I. Ali, T.A. Saleh, A.
Nayak, S. Agarwal, Chemical treatment
technologies for waste-water recycling—an
overview, RSC Advances 2 (16) (2012),
)6380–6388(.
[4] Iijima, S., 1991. Helical microtubules of
graphitic carbon. Nature 354 (6348), 56–58.
[5] Diallo, M.S., Savage, N., 2005.
Nanoparticles and water quality. J.
Nanoparticle Res. 7 (4-5), (325–330). [6] Upadhyayula, V.K.K., Deng, S., Mitchell,
M.C., Smith, G.B., 2009. Application of carbon
nanotube technology for removal of
contaminants in drinking water: a review. Sci.
Total Environ. 408 (1), (1–13).
[7] Di, Z.C., Ding, J., Peng, X.J., Li, Y.H.,
Luan, Z.K., Liang, J., 2006.
Chromium adsorption by aligned carbon
nanotubes supported ceria nanoparticles.
Chemosphere 62 (5), (861–865).
[8] Li, Y.H., Ding, Z., Luan, K., Di, Z.C.,
Zhu, Y.F., Xu, C.L., et al., 2003.
Competitive adsorption of Pb2+
, Cu2+
and
Cd2+
ions from aqueous solutions by
multiwalled carbon nanotubes. Carbon 41
(14), (2787–2792).
ISSN No: 2309-4893 International Journal of Advanced Engineering and Global Technology
I Vol-05, Issue-02, March 2017
1636 www.ijaegt.com
[9] Peng, X.J., Luan, Z.K., Ding, J., Di,
Z.H., Li, Y.H., Tian, B.H., 2005.
Ceria nanoparticles supported on carbon
nanotubes for the removal of arsenate from
water. Mater. Lett. 59 (4), (399–403).
[10] Lu, C.S., Chung, Y.L., Chang, K.F.,
2005. Adsorption of trihalomethanes from
water with carbon nanotubes. Water Res. 39
(6), (1183–1189).
[11] Yan, H., Gong, A.J., He, H.S., Zhou, J.,
Wei, Y.X., Lü, L., 2006. Adsorption of
microcystins by carbon nanotubes.
Chemosphere 62 (1), (142–148).
[12] Brady-Estévez, A.S., Kang, S.,
Elimelech, M.A., 2008. Singlewalledcarbon
nanotube filter for removal of viral and
bacterial pathogens. Small 4 (4), (481–484).
[13] Brady-Estévez, A.S., Schnoor, M.H.,
Vecitis, C.D., Saleh, N.B., Ehmelech, M.,
2010a. A multiwalled carbon nanotube
filter: improving viral removal at low
pressure. Langmuir 26 (18), (14975–14982).
[14] Brady-Estévez, A.S., Schnoor, M.H.,
Kang, S., Elimelech, M., 2010b. SWNT-
MWNT hybrid filter attains high viral
removal and bacterial inactivation.
Langmuir 26 (24), (19153–19158).
[15] Rahaman, M.S., Vecitis, C.D.,
Elimelech, M., 2012. Electrochemical
carbon nanotube filter performance toward
virus removal and inactivation in the
presence of natural organic matter. Environ.
Sci. Technol. 46 (3), (1556–1564) [16] Li, Y-H., Ding, J., Luan, Z., Di, Z., Zhu, Y.,
Xu, C, Wu, D., Wei, B., (2003a). Competitive
adsorption of Pb 2+
, Cu2+
and Cd2+
ions from
aqueous solutions by multiwalled carbon
nanotubes. Carbon 41, (278-2792).
[17] Lu, C., Su, F., (2007). Adsorption of natural
organic matter by carbon nanotubes. Separation
and Purification Technology 58, (113-121).
[18] Yuan, C. G., Zhang, Y., Wang, S.,
Chang, A., (2011). Separation and
preconcentration of palladium using
modified multi-walled carbon nanotubes
without chelating agent. Microchim Acta
173, (361-367).
[19] Ihsanullah, A. Abbas, A. Al-Amer, T.
Laoui, J. Al-Marri, Mu. S. Nasser, M.
Khraisheh, M. Atieh, (2016). Heavy metal
removal from aqueous solution by advanced
carbon nanotubes: Critical review of
adsorption applications. Separation and
Purification Technology 157, (141–161). [20] Akhavan, O., Abdolahad, M., Abdi, Y.,
Mohajerzadeh, S., 2011. Silver nanoparticles
within vertically aligned multi-wall carbon
nanotubes with open tips for antibacterial
purposes. J. Mater. Chem. 21 (2), )387–393(.
[21] Lee, C., Baik, S., (2010). Vertically-aligned
carbon nano-tube membrane filters with
superhydrophobicity and superoleophilicity.
Carbon 48 (8), (2192 – 2197).
[22] Schoen, D.T., Schoen, A.P., Hu, L.B.,
Kim, H.S., Heilshorn, S.C., Cui, Y., 2010.
High speed water sterilization using one-
dimensional nanostructures. Nano Lett. 10
(9), 3628–3632.
[23] Kang, S., Herzberg, M., Rodrigues,
D.F., Elimelech, M., 2008a. Antibacterial
effects of carbon nanotubes: size does
matter. Langmuir 24 (13), )6409–6413(.
[24] Kang, S., Mauter, M.S., Elimelech, M.,
2008b. Physicochemical determinants of
multiwalled carbon nanotube bacterial
cytotoxicity. Environ. Sci. Technol. 42 (19),
7528–7534.
[25] Kang, S., Mauter, M.S., Elimelech, M.,
2009. Microbial cytotoxicity of carbon-
based nanomaterials: implications for river
water and wastewater effluent. Environ. Sci.
Technol. 43 (7), )2648–2653(.
[26] Brady-Estévez, A.S., Nguyen, T.H.,
Gutierrez, L., Elimelech, M., 2010c. Impact
of solution chemistry on viral removal by a
single-walled carbon nanotube filter. Water
Res. 44 (13), )3773–3780(.
[27] J.Kim, Ha Kim, Jieun Kim, S. Lee, H.
Park, (2016). A nanofilter composed of
carbon nanotube-silver composites for virus
removal and antibacterial activity
improvement. Jor. Of Env. Science 42
(275– 283).